No, this is just parents who are afraid of their personal worldview being challenged by their own kids (oh the insolence!).

Nobody came to these parents to tell them "your kid should not be reading X". If parents don't trust/like the curriculum of their local school, AFAIK homeschooling is still an option in the US.

Parents already have that. They are now trying to limit it for other children.

Why should I be allowed to deny your children access to books at school?

Ah, so these parents should be able to say their child shouldn't read a biology textbook that discusses the theory of evolution?

Nonono. They’re saying your child shouldn't read a biology textbook that discusses the theory of evolution.

Ah yes, the slipper slope. Let's be honest, librarians and educators have a ton of power and no oversight in indoctrinating children into the views that they want. Now that parents are challenging them, all of sudden, PEN America believes that parents should have no say on the material their kids read.

It's not a slippery slope. That is literally what you are advocating. The same parents who don't want their children to know what Ruby Bridges went through or that gay people exist also don't want their children to learn about evolution.